In a liquid-crystal manufacturing apparatus and semiconductor manufacturing apparatus, for example, a step is required to wash, with a high purity level, an object to be processed, such as a glass substrate for a liquid crystal and semiconductor wafer. In order to wash and dry the above-mentioned material, it has been practiced that the object, while being spun, is washed by jetting a processing solution, such as pure water, and is dried while being spun without jetting the processing solution.
In order to perform such processing, use has been made of the spin-processing apparatus. The spin-processing apparatus has a cup body. Within the cup body a rotation body is provided which is rotationally driven by the rotation drive mechanism. The material is retained on the upper surface side of the rotation body. Above the cup body a nozzle is provided for jetting a processing solution onto the object.
Therefore, it is possible to wash-process the upper whole surface of the object by jetting the processing solution from the nozzle onto the object.
For example, in the case where the object is wash-processed with a chemical solution, after the wash-processing has been done with the chemical solution, the object is jetted with pure water as the processing solution to perform rinse-processing and, while being spun without supplying the processing solution, the rinse-processed material is dry-processed.
There is sometimes the case where, through the spinning of the rotation body and jetting of-the processing solution onto the object, a mist is produced and re-deposited onto the wash- and dry-processed object and the resultant object is contaminated.
It has been practiced that an exhaust tube is connected to the bottom of the cup body to allow the mist which is floated within the cup body to be sucked and exhausted and, by doing so, the mist is prevented from being redeposited on the object to be processed.
Incidentally, the mist is scattered at high speeds from the spinning material outwardly toward a diameter direction and collides against the inner wall surface of the cup body and is reflected. The mist reflected on the inner wall surface of the cup body is sucked into the above-mentioned exhaust tube and exhausted from within the cup body.
Since, however, the mist reflected on the inner wall surface of the cup body is indefinite in direction, part of the mist is scattered in the cup body to a site on which a suction produced at the exhaust tube is not exerted. For this reason, there is sometimes the case where the mist part is redeposited on the object without being borne on an air current in the cup body.
The above-mentioned cup body comprises a lower cup and an upper cup mounted on the lower cup to be up/down movable. In the case where the object is attached to and detached from the rotation body, the upper cup is lowered to expose the rotation body and the attachment/detachment is done by, for example, a robot.
According to the cup body thus structured, in order for the upper cup to have an up/down movable structure, a clearance has to be created between the lower cup and the upper cup. There is sometimes the case where when a suction force is created at the exhaust tube so as to discharge a gas within the cup body, outer air is sucked from the clearance between the lower cup and the upper cup. Since a dust is contained in the outer air passed through the clearance between the lower cup and the upper cut, the object to be processed is sometimes contaminated thereby.
It is to be noted that when the upper cup is moved in an up/down motion without creating a clearance between the lower cup and the upper cup, a dust is produced due to their slide motion and it is unavoidably deposited onto the object . From this viewpoint it is better to create a clearance.
In the case where a gas within the cup body is sucked and exhausted by the exhaust tube, if the direction in which an air flow is produced within the cup body and direction in which a suction is created by the exhaust tube within the cup body differ, there is sometimes the case where the mist within the cup body is less likely to flow smoothly into the exhaust tube. As a result, the mist is floated within the cup body and, sometimes, it is deposited on the object to be processed.